The light sources emitting non-classical light such as triggered single photons, entangled-photon pairs and squeezed photons are the key components of various quantum technology protocols including quantum key distribution, quantum teleportation and quantum metrology. In recent years, a self-assembled semiconductor quantum dot embedded in the cavity has emerged as a leading source of non-classical light. In this talk, I shall present our recent theoretical works on the generation of single photons and squeezed photons using quantum dot-cavity systems. The possible immediate future research potential in this area shall also be described.